A three dimensional die with multiple layers, as one example of an electrical circuit, requires electrical connections to the multiple layers. For example, wire bonds serve to provide the electrical connections between the layers. In some cases, the wire bonds must be made to contacts on both the top and bottom of the die. Having wire bond contacts on both the top and bottom of the die can result in the need to fabricate subassemblies with wire bonds wrapping around multiple sides of the die. Having wire bonds that wrap around multiple sides of a die makes the die difficult to package. Having wire bonds wrap around the die increases the periphery of the die. Having a larger periphery increases the space used by the die when the die is mounted to a substrate, circuit board, or the like. In addition, wire bonds are very thin and therefore susceptible to stress damage.
In another example, the die is packaged in a housing with electrical feed throughs. Wire bond contacts are made to electrical contacts on different layers of the die. These bond wires are then attached to feed throughs in the housing. The feed throughs in the housing allow for an interface with a substrate, circuit board, or the like. Creating the wire bonds and electrical feed through is complicated to assemble, expensive, and fragile.
In another example, the die has one or more layers. The die makes an electrical connection to a substrate, circuit board, or the like, of a different material than the die. Since the materials are different, they are likely to have different expansion/contraction coefficients. When expansion occurs in one or both of the materials, a stress is placed on the connection between the two materials. When the stress is large enough the connection can fail or break.
In another example, the die makes an electrical connection to a substrate, circuit board, or the like. When translational or rotational movement occurs a stress is placed on the connection between the die and the substrate, circuit board, or the like.
Thus, a need exists for a die that has increased durability in the interface between the die and a compatible structure. A need also exists for a die with decreased size. A need also exists for a die that is easier to electrically interface with compatible structures.